This invention relates, in general, to input/output (I/O) processing, and in particular, to controlling access to input/output adapters of a computing environment.
Many system architectures that use input/output adapters control access to those adapters by using central processing unit (CPU) based address translation mechanisms. In such systems, memory mapped input/output (MMIO) is used, and the hardware knows, based on the manner in which the memory is set up, whether an instruction executed by a processor is pointing to real memory or whether it is actually pointing to memory in one of the adapters. The hardware is then able to steer it accordingly.
Some systems, however, may not use the traditional memory mapped I/O.